Comment on If a planet was completely covered in water, wouldn't it all be freshwater?
meco03211@lemmy.world 4 weeks agoBut that’s not what’s happening. There’s no “mining” of salt. There’s no significant addition or loss of salt to the ocean. Salt just stays in the oceans here. Freshwater will evaporate and return through rivers and rain. On a planet without land, the salt would still remain in the ocean.
HotDayBreeze@lemmy.world 4 weeks ago
Salt gets into rivers when material that can’t be dissolved is stripped away by erosion. This exposes new water soluble compounds to the water, where they dissolve into the water and are taken to the ocean.
Over millions of years erosion removes innumerable tons of material, essentially mining the subsurface soluble compounds and delivering them to the ocean. Once there, as you mention ,those salts remain in the ocean. On Earth, this process began billions of years ago and has been adding salt to the oceans ever since.
However without that land based salt mining process, how salty would the oceans be? Lots of good clues in this thread, but I don’t think anyone has offered a definitive answer.
meco03211@lemmy.world 4 weeks ago
Ah. I see the angle you’re coming from. I had mentioned in another comment somewhere that essentially all salt without an impermeable barrier between it and the water on this planet would be dissolved (provided it doesn’t saturate the water which would be a horrifically enormous amount of salt). Salt is highly soluble in water and on any timescale that could be relevant would fully dissolve and achieve a general equilibrium. If the planet has water, then it has a star able to warm the planet. There’s no realistic scenario that wouldn’t result in the ocean fully mixing.